"of Ionia," the districts of ancient Greece inhabited by the Ionians (including Attica and the north coast of the Peloponnesus, but especially the coastal strip of Asia Minor, including the islands of Samos and Chios). The name (which Herodotus credits to an ancestral Ion, son of Apollo and Creusa) probably is pre-Greek, perhaps related to Sanskrit yoni "womb, vulva," and a reference to goddess-worshipping people.

Also used of the sea that lies between Italy and the northern Peloponnesus (1630s). The musical Ionian mode (1844) corresponds to our basic major scale but was characterized by the Greeks as soft and effeminate, as were the Ionians generally.

The Ionians delighted in wanton dances and songs more than the rest of the Greeks ... and wanton gestures were proverbially termed Ionic motions. [Thomas Robinson, "Archæologica Græca," 1807]